Electric connector



June 6, 1961 s. E. DAVIS 2,987,697

ELECTRIC CONNECTOR Filed Oct. 11, 1957 ited States Patent 2,987,697 ELECTRIC CONNECTOR Stafford E. Davis, Newtonville, Mass., assignor to Ark- Les Switch Corporation, Watertown, Mass., a corporation of Massachusetts Filed Oct. 11, 1957, Ser. No. 689,607 3 Claims. (Cl. 339-258) This invention relates to electric connectors consisting of two members adapted to be secured to the ends of wires or other conductors which are to be electrically connected, and more particularly to an improved female connector member to be used with a cooperating flat spade member to provide an eflicient assembled electrical connector of extraordinarily small size. These members are constructed so that they can be pushed together into mutual engagement so as to make a good electrical connection which can readily be broken and remade as desired.

Heretofore known connectors of the type shown, for example, in the US. patent to Batcheller, No. 2,600,190 are generally satisfactory as connector elements in sizes down to about inch in length and 1 inch in width. However, they cannot be economically manufactured in smaller sizes, principally due to the minute and highly accurate tools which would be required to punch the two parallel slots in the floor portion of the element and to cold swage the strip therebetween to provide the hard and resilient arch upon which the connector depends for its superior performance.

Accordingly, it is an object of the present invention to provide an eflicient electrical connector having elements no more than about /2 inch in length and /8 inch in width, that is, less than half the width of the conventional connectors discussed above, and yet to take advantage of the properties imparted by a cold swaging operation to give increased hardness and resiliency. It is a particular feature of the connector of the invention that its manufacture does not require especially minute or highly accurate tools, so that as a result, it may be economically manufactured.

It is another object of the invention to provide a connector having means engageable by an assembly tool to facilitate the assembly of the connector elements which otherwise is a problem due to their minute size.

It is yet another object of the invention to provide a connector having means limiting the extent of engagement of the elements thereof also to facilitate their assembly, particularly by automatic machinery.

These objectives are realized in the connector hereinafter described and illustrated on the drawing, in which:

FIG. 1 is a perspective view of two parts of a preferred embodiment of an electric connector mounted on wires for use;

FIG. 2 is a top plan view of the female member of the connector shown in FIG. 1;

FIG. 3 is a section on line 3-3 of FIG. 2;

FIG. 4 is a bottom plan view of the member shown in FIG. 1;

FIG. 5 is a section on the line 5-5 of FIG. 3;

FIG. 6 is a diagrammatic section similar to that of FIG. 5 but showing a step in the manufacture of the member of FIGS. 2 through 5; and

FIG. 7 is a modification of the connector of FIG. 1.

In the connector shown in FIG. 1, the male member generally indicated at 10 is of a well-known form consisting of a flat tongue of sheet metal. The tongue has an extension 14 which is curled around the stripped end portion of a wire and its insulation and is pressed to grip such end portion, providing shoulders 15 at the back of the tongue engageable by a tool to facilitate assembly. Preferably, as shown, said member is somewhat tapered longitudinally, with its side margins or edges 16 tapering inwardly from the end adjacent extension 14 toward its free end 18, although a straight member 10 may also be used as hereinafter described with reference to FIG. 7.

Cooperating with the member 10 is a female member generally indicated at 20 which is preferably made of a single piece of sheet metal. The sheet metal is preferably copper or a copper-containing alloy, such as half-hard brass or half-hard bronze (as these alloys are known in the art), these alloys being sufficiently malleable to be capable of being sharply bent without cracking. Suitably shaped blanks are stamped from a sheet or strip of such material and side flanges 22 and 24 are bent upward and inward from the margins of a tapered plane floor portion 26 to form a tapered or wedge-shaped channel having a plane bottom or floor 26 with flanges which overhang portions of the floor 26 so that the side margins 16 of the male member 10 can be snugly fitted between the overhanging flanges and the floor of the member 20. Suitable extensions 30 and 31 at an end of the floor 26 are shaped into channel form so as to form a ferrule ready to be crimped around the stripped end of a wire and its insulation to grip them as indicated in FIG. I, and the rear ends of the inturned flanges 22 and 24 are bent up to form rearwardly extending lugs 23 and 25 above the level of the ferrule so that they are engageable by an assembly tool to facilitate assembly of the connector elements.

In the channel floor portion 26 is cut a single central narrow longitudinal slot 34 defining strips 36 and 38 each forming a part of floor 26 on a side of slot 34 adjacent flanges 22 and 24, respectively. Preferably, the slot 34, as shown, has a length to width ratio of about 3 to 1 and is wider at its ends than at its midpoint with the midpoint width being about half of the slot width so that the strips 36 are somewhat wider at their midpoints than at their ends forming a generally shallow V shaped edge having an included angle of about degrees and pointing toward the midpoint of the longitudinal center line of slot 34.

As shown in FIG. 6, the partially finished blank then has positioned within it a suitable anvil 40 which has a suitably longitudinally tapered top face with a central dimple or depression 42. The width of the anvil 40 is such as to fit within the flanges 22 and 24, and the length of the anvil is substantially the same as that of said flange.

A die 44 is caused to strike the portion of the floor 26 which is supported by the anvil 40. This die has a working face with a boss 46 which is complementary to the dimple 42. The die is caused to strike the floor of the connector member with a considerable force so that the blow flattens the central portions of the strips 36 and 38 to about two-thirds of the stock thickness of the metal sheet to form on each strip a generally semicircular domed protuberance 50 and 51 on strips 36 and 38 respectively, with its diameter generally along said slot, said protuberances preferably having a common center at 52 within said slot. In thus being swaged, this portion of the floor is bent out of the plane of said floor upwardly toward the flanges and is spread out laterally in the process of being thinned so that the slot is somewhat closed to about half of its width before swaging at that point providing a 4 to 1 slot length to width ratio to form a narrow slit at its midpoint. This swaging operation serves to harden the metal thus flattened and to impart to it a greatly increased resilience. In other words, the elastic limit of the swaged metal is considerably increased. In terms of function, this means that if the original metal is deformed by being sprung repeatedly away from its normal plane position by the insertion and withdrawal of a complemental member 10, it soon fails to return fully to its normal position. After the metal in this area Patented June 6, 1961 enemas? I has been swaged, it returns to its normal position after a very large number of similar displacements.

The complemental members are assembled by pressing them together, preferably by means of suitable tools engaging shoulders 15 of member and lugs 23 and 25 of member 20, the cooperating tapered configuration preferably of the order of 12 degrees or somewhat less with respect to the axis of the members limiting the extent of engagement thereof as desired. At the desired point of engagement, with the side margins 16 of member 10 in contact with the flanges 22 and 24 of member 20, the domed protuberances 50 and 51 which rise from the floor portion strips are pressed against the male member when the latter is assembled with the member 20 so as to hold the members more firmly secured together but to permit the members to be separated when sufiicient force is used to pull them apart.

In FIG. 7 is shown a similar arrangement but with a male member 10 and female member 20' of rectangular form, but otherwise identical to the tapered configuration above described, similar reference numerals but with prime marks being applied thereto. In this instance, however, since the tapered configuration is not used to hold the two members firmly together, the male member 10' has a recess 12 adapted to receive the domed protuberances 50 and 51 to hold the two elements together.

Thus, it will be seen that the invention provides a novel female connector member of extraordinarily small size. Various modifications within the spirit of the invention and the scope of the appended claims but not herein described will be apparent to those skilled in this art.

I claim:

1. An electric connector member comprising a piece of malleable sheet metal having longitudinal edge portions sharply bent upward and inward to form a channel having a plane bottom with overhanging fianges having bent up rearwardly extending tool engageable lug means at the rear ends thereof, said channel bottom having therein a single central narrow longitudinal slot and having a length to width ratio of 3 to 1 wider at its ends than at its midpoint defining a strip on each side thereof wider at its midpoint than at its ends and with a generally shallow V shaped edge pointing toward the longitudinal center line of said slot, a portion of each of said strips adjacent the midpoint thereof at said slot being bent out of the plane of said bottom upwardly toward said flanges and being thinner and harder than said channel bottom, said portions each being in the form of domed protuberances of generally semicircular configuration with their diameter generally along said slot and having a common center within said slot.

2. An electric connector member as claimed in claim 1 wherein said channel is tapered.

3. An electric connector member as claimed in claim 1 wherein said channel is rectangular.

References Cited in the file of this patent UNITED STATES. PATENTS 2,600,188 Batcheller June 10, 1952 2,600,190 Batcheller June 10, 1952 2,759,165 Batcheller Aug. 14, 1956 2,816,275 Hammell Dec. 10, 1957 FOREIGN PATENTS 1,137,079 France Nov. 25, 1955 

